Anyone know what is going on here????

[CB06]

Tried setting up a cheap diy ato with jsut a measuring cup hanging on side of tank with some airline tubing and flow valve on the end. I started the siphon and got the drip rate where I wanted it before putting the other end in the tank. When I did this the siphon reversed even tho the measuring cup was higher then the other end of the airline tubing what is happening???

 

[blaxsun]

You may want to upload an image or two of the setup for people to offer suggestions.

 

[Pkunk35]

Is the tube in the tank? If so need to suspend above to avoid siphoning

 

[exnisstech]

I don't see how that is possible as water will not flow up hill. Unless the bottom of the cup is below the surface level of the tank. That would allow a syphon into the cup if the hose end is close to the bottom of the cup. The end of the hose has to be higher than the surface level of the tank.

 

[CB06]

Ended up finding a detention on google and definitely haven’t heard of this before but this is what it said ‘The traditional theory for centuries was that gravity pulling the liquid down on the exit side of the siphon resulted in reduced pressure at the top of the siphon. Then atmospheric pressure was able to push the liquid from the upper reservoir, up into the reduced pressure at the top of the siphon, like in a barometer or drinking straw, and then over.’

 

[AFHokie]

Ended up finding a detention on google and definitely haven’t heard of this before but this is what it said ‘The traditional theory for centuries was that gravity pulling the liquid down on the exit side of the siphon resulted in reduced pressure at the top of the siphon. Then atmospheric pressure was able to push the liquid from the upper reservoir, up into the reduced pressure at the top of the siphon, like in a barometer or drinking straw, and then over.’

I could see that happening if the upper reservoir was airtight. As the water goes down the internal pressure would decrease, but if it's a measuring cup I can't imagine it was sealed off.

 

[All_talk]

Water will always level at the surface across the siphon. The height and depth of the containers, nor the depth of the ends of the siphon tube control the flow direction. The top of the water surface in one container will try and level to the surface in the other.

Are you saying that the surface of the water in the cup went higher than the surface in the tank?

 

[CB06]

Water will always level at the surface across the siphon. The height and depth of the containers, nor the depth of the ends of the siphon tube control the flow direction. The top of the water surface in one container will try and level to the surface in the other.

Are you saying that the surface of the water in the cup went higher than the surface in the tank?

Ok now I can see what was happening as the siphon sucked the water level in the cup below the tanks water level it reversed the cycle I must have to mount the cup somewhere higher.